In recent years, with the micro-miniaturization of semiconductor devices, substrates having a microstructure (substrates formed with various material films having different physical properties) have been fabricated. For example, at a damascene interconnect forming step of filling a wiring gutter formed on a substrate with metal, after the formation of damascene interconnect, excess metal is polished and removed by a substrate polishing apparatus (a chemical mechanical polishing (CMP) apparatus), and various material films having different physical properties (a metal film, a barrier film, an insulating film, etc.) are formed on the surface of the substrate. On the surface of this substrate, there exist a residue of slurry used in CMP and metal swarf (Cu swarf or the like) resulting from the CMP. Therefore, if cleaning of the surface of the substrate is not thoroughly done, such as when the surface of the substrate is complicated and difficult to be cleaned, leakage or adhesion failure is caused by the effect of the residue, etc., which may cause a decrease in reliability. Accordingly, in a CMP apparatus that polishes a semiconductor substrate, at a cleaning step after polishing, roller-member scrubbing or pen-member scrubbing is performed.
As for the roller-member scrubbing, there is known the following procedure: a load cell for measuring the load on a roller member is installed between a lifting unit of a lift mechanism and a roller member holder, and the load on the roller member is controlled to be fed back through a control device of an actuator on the basis of the value measured by the load cell (for example, see JP 2014-38983 A).